Making a Worm Farm
Composting worms are just about the hardest workers in a garden but farming them is easy! A worm farm will provide a constant supply of free fertiliser and reduce the amount of landfill. It is estimated that an average home with a worm farm would reduce its compostable garbage by up to one tonne per person per year.
Worm farms are easy to make out of wooden or polystyrene boxes but commercially made kits are convenient and have the advantage of liquid run-off taps that allow the ‘worm wee’ to be collected as well. A worm farm is made up of levels of containers starting with a solid base and then holes in each of the upper layers. The aim is to build layers for the worms to move through but still allow the liquid and worm castings to be collected at the bottom.
Worms are hermaphrodites. Each worm has both male and female sex organs. They have no eyes but can sense vibrations, light and temperature through their skin. They also breathe through their skin and expel urine through special pores. Worms are exceptional composters because they have a long gut running from one end to the other. It squeezes the food particles until the nutrients are absorbed, discarding the rest as castings.
The numbers in a worm farm can double every two months but once it reaches capacity they will stop breeding and only start again once some worms are removed or another layer is added.
Worm farms should be positioned in a cool, dry space but not in the hot afternoon sun. Ensure that the farm is raised off the ground with bricks or on a stand to avoid any moisture causing damage to the floor and easy access for rodents.
Worms from the garden are not suitable for worm farms. Composting worms (Tiger or Red worms) are available in bulk from Better Pets and Gardens with a small bag holding around 500 worms and some bedding material. Line the bottom of the worm farm with two sheets of newspaper then fill it half way with compost, grass clippings and moist, shredded newspaper then spread the worms and the bedding mixture over the top.
Only feed a little at this stage using vegetable scraps from the kitchen. Then, place a layer of wet newspaper or hessian over the top to keep them moist and cover with the lid. The worms will start to feed and after about two weeks the amount of organic material added can be increased.
It is best to feed the worms weekly but each time, cover the organic scraps with compost or soil to avoid attracting vermin. If the farm is too dry or has ants, add more vegetable matter that rots down and add water more regularly. If vinegar flies become a problem, the mix has become too acidic so add some lime through the top few centimetres.
As each layer fills up with worms and soil, add another level to the farm making sure that there are holes for the worms to move through. Place food with compost into each new level to encourage the worms in. It will take a few months for all the worms to relocate into the upper level allowing the castings to be harvested from the bottom.
Worms are quite clean creatures. They do not carry diseases and in fact, their digestive system destroys disease-causing pathogens.
Worm castings or vermicast can be collected from the bottom level of the farm after about four or five months. To get the worms out before putting the castings into the garden, put it in the sunlight and scrape the top layer off. The worms will tunnel down to get out of the light.
Worm castings are a powerful fertiliser. A handful is enough to sprinkle around a shrub or pot plant which will thrive. Cover it with mulch or soil after applying.
The liquid run-off, or ‘worm wee’, can also be collected in bottles and used for watering pot plants or spraying on to foliage. It needs to be strained through a stocking and diluted at 10 to 1 first.
Worms will eat just about any type of fruit and vegie scraps, shredded paper, leaves, damp cardboard and coffee grinds. They even enjoy pet hair, crushed egg shells and vacuum cleaner bags.
Avoid feeding worms too much as this will lead to odour problems but whilst they will eat many things, don’t add citrus or onions. Meat, dairy products, salty food should be avoided as these will attract vermin and avoid plant material that has been contaminated with toxic chemicals.
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